#!/bin/sh # This is a shell archive (produced by GNU sharutils 4.2). # To extract the files from this archive, save it to some FILE, remove # everything before the `!/bin/sh' line above, then type `sh FILE'. # # Made on 2000-03-19 15:00 EST by <jcej@chiroptera.tragus.org>. # Source directory was `/home/jcej/projects/ACE_wrappers/docs/tutorials/012'. # # Existing files will *not* be overwritten unless `-c' is specified. # # This shar contains: # length mode name # ------ ---------- ------------------------------------------ # 430 -rw-rw-r-- hdr # 56 -rw-rw-r-- bodies # 1090 -rw-rw-r-- page01.pre # 262 -rw-rw-r-- page02.pre # 395 -rw-rw-r-- page03.pre # 154 -rw-rw-r-- page04.pre # 182 -rw-rw-r-- page05.pre # 448 -rw-rw-r-- page06.pre # 393 -rw-rw-r-- page02.pst # 398 -rw-rw-r-- page03.pst # 162 -rw-rw-r-- page04.pst # 447 -rw-rw-r-- page05.pst # save_IFS="${IFS}" IFS="${IFS}:" gettext_dir=FAILED locale_dir=FAILED first_param="$1" for dir in $PATH do if test "$gettext_dir" = FAILED && test -f $dir/gettext \ && ($dir/gettext --version >/dev/null 2>&1) then set `$dir/gettext --version 2>&1` if test "$3" = GNU then gettext_dir=$dir fi fi if test "$locale_dir" = FAILED && test -f $dir/shar \ && ($dir/shar --print-text-domain-dir >/dev/null 2>&1) then locale_dir=`$dir/shar --print-text-domain-dir` fi done IFS="$save_IFS" if test "$locale_dir" = FAILED || test "$gettext_dir" = FAILED then echo=echo else TEXTDOMAINDIR=$locale_dir export TEXTDOMAINDIR TEXTDOMAIN=sharutils export TEXTDOMAIN echo="$gettext_dir/gettext -s" fi touch -am 1231235999 $$.touch >/dev/null 2>&1 if test ! -f 1231235999 && test -f $$.touch; then shar_touch=touch else shar_touch=: echo $echo 'WARNING: not restoring timestamps. Consider getting and' $echo "installing GNU \`touch', distributed in GNU File Utilities..." echo fi rm -f 1231235999 $$.touch # if mkdir _sh32620; then $echo 'x -' 'creating lock directory' else $echo 'failed to create lock directory' exit 1 fi # ============= hdr ============== if test -f 'hdr' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'hdr' '(file already exists)' else $echo 'x -' extracting 'hdr' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'hdr' && <HTML> <HEAD> X <META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"> X <META NAME="Author" CONTENT="James CE Johnson"> X <TITLE>ACE Tutorial 012</TITLE> </HEAD> <BODY TEXT="#000000" BGCOLOR="#FFFFFF" LINK="#000FFF" VLINK="#FF0F0F"> X <CENTER><B><FONT SIZE=+2>ACE Tutorial 012</FONT></B></CENTER> X <CENTER><B><FONT SIZE=+2>Passing classes through ACE_Message_Queue</FONT></B></CENTER> X X <P> <HR WIDTH="100%"> SHAR_EOF $shar_touch -am 03191459100 'hdr' && chmod 0664 'hdr' || $echo 'restore of' 'hdr' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'hdr:' 'MD5 check failed' 1acf94beccfa9e953b2f55e02a0bb2e6 hdr SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'hdr'`" test 430 -eq "$shar_count" || $echo 'hdr:' 'original size' '430,' 'current size' "$shar_count!" fi fi # ============= bodies ============== if test -f 'bodies' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'bodies' '(file already exists)' else $echo 'x -' extracting 'bodies' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'bodies' && PAGE=2 work.h block.h message_queue.cpp task.h task.cpp SHAR_EOF $shar_touch -am 0124160199 'bodies' && chmod 0664 'bodies' || $echo 'restore of' 'bodies' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'bodies:' 'MD5 check failed' 3ad29f0a25bfe156b37630c9ee9f715c bodies SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'bodies'`" test 56 -eq "$shar_count" || $echo 'bodies:' 'original size' '56,' 'current size' "$shar_count!" fi fi # ============= page01.pre ============== if test -f 'page01.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page01.pre' '(file already exists)' else $echo 'x -' extracting 'page01.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page01.pre' && <P> Last time around we put an object into a message queue by using the copy() method to create a duplicate of the object. That's probably OK for simple objects that aren't very large. However, if you have an object that contains pointers or tons of data then that approach is going to cause problems. <P> What we'll do in this tutorial is specialize the ACE_Message_Block object so that it can carry our data more efficiently. As you'll see, this isn't very difficult at all. <P> Kirthika's abstract: <UL> Here, a Message_Block class is derived from ACE_Message_Block and is used to hold a pointer to the object of class Work. Also, the block has a header containing text. This example simply illustrates a cleaner way of utilizing Message_Blocks to store objects rather than copying their contents. <P> The ACE_Barrier class has been used in the Task class which blocks the threads until all of them are rearing to go and grab a block from the queue and process it. <P> Thus a message queue can be used to accomplish a variety of tasks by storing a object pointer in the blocks. </UL> SHAR_EOF $shar_touch -am 03191459100 'page01.pre' && chmod 0664 'page01.pre' || $echo 'restore of' 'page01.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page01.pre:' 'MD5 check failed' c9933ac2153b0a56043967ea9c7eb0c9 page01.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page01.pre'`" test 1090 -eq "$shar_count" || $echo 'page01.pre:' 'original size' '1090,' 'current size' "$shar_count!" fi fi # ============= page02.pre ============== if test -f 'page02.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page02.pre' '(file already exists)' else $echo 'x -' extracting 'page02.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page02.pre' && We normally start by looking at main() and work our way out from there. This time, I want to start by showing you the ACE_Message_Block derivative but before that, I have to introduce you to the Work object and it's baseclass Unit_Of_Work <P> <HR WIDTH="100%"> SHAR_EOF $shar_touch -am 03191459100 'page02.pre' && chmod 0664 'page02.pre' || $echo 'restore of' 'page02.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page02.pre:' 'MD5 check failed' 91f6bbd4cdf687d420bd52bf6685e2d2 page02.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pre'`" test 262 -eq "$shar_count" || $echo 'page02.pre:' 'original size' '262,' 'current size' "$shar_count!" fi fi # ============= page03.pre ============== if test -f 'page03.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page03.pre' '(file already exists)' else $echo 'x -' extracting 'page03.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page03.pre' && <P> In the previous tutorial we moved our complex data into the queue by copy()ing it directly into the message block's data area. I hope that most readers got a queasy feeling when I did that. It just isn't a good idea... <P> A better idea would be to teach the message queue about our data types (or at least a baseclass) so that it can more efficiently handle things: <P> <HR WIDTH="100%"> SHAR_EOF $shar_touch -am 03191459100 'page03.pre' && chmod 0664 'page03.pre' || $echo 'restore of' 'page03.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page03.pre:' 'MD5 check failed' 134a60947715be2de3ca2589a3e652e2 page03.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pre'`" test 395 -eq "$shar_count" || $echo 'page03.pre:' 'original size' '395,' 'current size' "$shar_count!" fi fi # ============= page04.pre ============== if test -f 'page04.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page04.pre' '(file already exists)' else $echo 'x -' extracting 'page04.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page04.pre' && <P> Ok, finally we get to main(). Sorry for the diversion but it was important to lay some of that groundwork before getting here. <P> <HR WIDTH="100%"> SHAR_EOF $shar_touch -am 03191459100 'page04.pre' && chmod 0664 'page04.pre' || $echo 'restore of' 'page04.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page04.pre:' 'MD5 check failed' 8989e75934f20e9b74d38a2d3687613a page04.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pre'`" test 154 -eq "$shar_count" || $echo 'page04.pre:' 'original size' '154,' 'current size' "$shar_count!" fi fi # ============= page05.pre ============== if test -f 'page05.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page05.pre' '(file already exists)' else $echo 'x -' extracting 'page05.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page05.pre' && <P> The Task is the only object we've not been through yet. I'll go ahead and show both the header and cpp on this one page since the header isn't very large. <P> <HR WIDTH="100%"> SHAR_EOF $shar_touch -am 03191459100 'page05.pre' && chmod 0664 'page05.pre' || $echo 'restore of' 'page05.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page05.pre:' 'MD5 check failed' ed1b82e232cc376efa7b78f391c893bd page05.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pre'`" test 182 -eq "$shar_count" || $echo 'page05.pre:' 'original size' '182,' 'current size' "$shar_count!" fi fi # ============= page06.pre ============== if test -f 'page06.pre' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page06.pre' '(file already exists)' else $echo 'x -' extracting 'page06.pre' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page06.pre' && <P> Once again, we come to the end of a tutorial. By creating a simple specialization of ACE_Message_Block, we've been able to remove a lot of complexity and erorr potential from our previous implementation. <UL> <LI><A HREF="Makefile">Makefile</A> <LI><A HREF="message_queue.cpp">message_queue.cpp</A> <LI><A HREF="work.h">work.h</A> <LI><A HREF="block.h">block.h</A> <LI><A HREF="task.h">task.h</A> <LI><A HREF="task.cpp">task.cpp</A> </UL> <P> SHAR_EOF $shar_touch -am 03191459100 'page06.pre' && chmod 0664 'page06.pre' || $echo 'restore of' 'page06.pre' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page06.pre:' 'MD5 check failed' 64afabb236ea02927914d03f258e620b page06.pre SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page06.pre'`" test 448 -eq "$shar_count" || $echo 'page06.pre:' 'original size' '448,' 'current size' "$shar_count!" fi fi # ============= page02.pst ============== if test -f 'page02.pst' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page02.pst' '(file already exists)' else $echo 'x -' extracting 'page02.pst' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page02.pst' && <HR WIDTH="100%"> <P> This is basically the same as the <i>DataBase</i> in the previous tutorial but I've changed the name to be more generic. The feeling is that a <i>Data</i> object would be a C struct but an <i>Work</i> object would be a class with methods. <P> Now that you know what we'll be putting into the queue, lets go to the next page where I specialize the ACE_Message_Block. <P> SHAR_EOF $shar_touch -am 03191459100 'page02.pst' && chmod 0664 'page02.pst' || $echo 'restore of' 'page02.pst' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page02.pst:' 'MD5 check failed' ab34347fca8c20953552cf0ecebd394f page02.pst SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page02.pst'`" test 393 -eq "$shar_count" || $echo 'page02.pst:' 'original size' '393,' 'current size' "$shar_count!" fi fi # ============= page03.pst ============== if test -f 'page03.pst' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page03.pst' '(file already exists)' else $echo 'x -' extracting 'page03.pst' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page03.pst' && <HR WIDTH="100%"> <P> Ok, this looks pretty good. We just construct our specialized Message_Block instead of the generic ACE_Message_Block and let it carry our data along. When our application is done with the message block and release()es it, we know that our work object will also be taken care of. <P> Let's now go to main() and see what we had to change there to use this specialization. <P> SHAR_EOF $shar_touch -am 03191459100 'page03.pst' && chmod 0664 'page03.pst' || $echo 'restore of' 'page03.pst' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page03.pst:' 'MD5 check failed' 01e400b5683e0e1c3dfa25cc8120bfa6 page03.pst SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page03.pst'`" test 398 -eq "$shar_count" || $echo 'page03.pst:' 'original size' '398,' 'current size' "$shar_count!" fi fi # ============= page04.pst ============== if test -f 'page04.pst' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page04.pst' '(file already exists)' else $echo 'x -' extracting 'page04.pst' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page04.pst' && <HR WIDTH="100%"> <P> That certainly looks cleaner than the previous approach! If you blink, you'll miss the part where the Work object goes into the Queue. <P> SHAR_EOF $shar_touch -am 03191459100 'page04.pst' && chmod 0664 'page04.pst' || $echo 'restore of' 'page04.pst' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page04.pst:' 'MD5 check failed' 245db1d5e74203bf085369bb47d646db page04.pst SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page04.pst'`" test 162 -eq "$shar_count" || $echo 'page04.pst:' 'original size' '162,' 'current size' "$shar_count!" fi fi # ============= page05.pst ============== if test -f 'page05.pst' && test "$first_param" != -c; then $echo 'x -' SKIPPING 'page05.pst' '(file already exists)' else $echo 'x -' extracting 'page05.pst' '(text)' sed 's/^X//' << 'SHAR_EOF' > 'page05.pst' && <HR WIDTH="100%"> <P> Like main() this is actually simpler than the previous tutorial. It's much cleaner to carry around a pointer to the object we're working with than to try copying data. <P> The only complication is the new ACE_Barrier. It's a pretty simple object that makes it easy for you to synch threads in this way. You could do some fancy tricks with mutexes, counters & semaphores but why bother when the Barrier already exists. <P> SHAR_EOF $shar_touch -am 03191459100 'page05.pst' && chmod 0664 'page05.pst' || $echo 'restore of' 'page05.pst' 'failed' if ( md5sum --help 2>&1 | grep 'sage: md5sum \[' ) >/dev/null 2>&1 \ && ( md5sum --version 2>&1 | grep -v 'textutils 1.12' ) >/dev/null; then md5sum -c << SHAR_EOF >/dev/null 2>&1 \ || $echo 'page05.pst:' 'MD5 check failed' a7f519237d11a25b28af7aa33f5aaf30 page05.pst SHAR_EOF else shar_count="`LC_ALL= LC_CTYPE= LANG= wc -c < 'page05.pst'`" test 447 -eq "$shar_count" || $echo 'page05.pst:' 'original size' '447,' 'current size' "$shar_count!" fi fi rm -fr _sh32620 exit 0